My 1991 Lexus LS400 requires premium.... it has a V8. I do not think the smaller Lexus that year (ES250) required premium, since it had the Camry engine).
As you can see on the photo of this LS400 instrument panel- it says "premium unleaded fuel only" above the fuel gauge..
....and now that you mentioned it, under the hood either my 72' Caprice and/or 73' Grand Ville, it says either 91 or 93 octane recommended, but I always run 87 in them. I guess its where they have the HP V8s in them. I will have to look into this. I had totally forgot about that!
Whats strange is that at least on the 72' it says it will run on "low lead" or "no lead" gas.
That's certainly odd. Not one of those cars you listed should require premium fuel.